Human thermo-physiological comfort assessment in Lisbon by local climate zones on very hot summer days

Extreme heat is a current and future issue on urban areas, with negative impacts health quality of life (increasing morbidity mortality rates). This paper analyses day (12:00–15:00 h) nighttime (00:00–03:00 thermo-physiological comfort (TC) conditions by Local Climate Zones (LCZ) in Lisbon during particular Weather Type (LWT), very hot summer days. For this, 13 different microscale sample areas were chosen covering non-urban land cover classes (LCZs 1–3, 4–6, 8, 9, A B). Universal Thermal Index (UTCI) Mean Radiant Temperature (MRT) modeled SkyHelios software for 163 days between 2008 2014. Results show that the all LCZ samples depict same average TC (average UTCI 34°C—strong stress) densely wooded are 2°C cooler 32°C—moderate stress). However, compact 1–3) low sky view factor some vegetation (street trees) display lower percentages area higher discomfort (TD) levels (83% strong stress against 98% LCZs 8 9 100% 4–6). When considering hottest (air temperatures equal or above 35°C—75th percentile), moderate class disappears appears only occupying 12% 16% 10%–22% 16%–22% 9. During period no thermal stress, favoring nocturnal physiological recovery. strongly influenced solar radiation wind, which explains need to increase shading area, preferably trees, promote preserve ventilation paths.